An Intrinsically‐Adhesive Family of Injectable and Photo‐Curable Hydrogels with Functional Physicochemical Performance for Regenerative Medicine

Abstract

Intrinsically adhesive hydrogels have various functions in biomedical areas particularly in minimally-invasive surgical treatments. [1,2] In these medical situations, bioadhesives have to present not only strong adhesion to wet tissues but specific ranges of injectability, degradability, swelling, biocompatibility, and mechanical match. [3,4] This is particularly challenging as the adhesive mechanism of the hydrogel should also allow proper material functionality in its bulk. The adhesion of hydrogels could be enhanced by strong bonds with the tissue as well as the material's capacity to dissipate energy. [5,6] Dissipative double-network hydrogels show high adhesion when either the tissue or the hydrogel substrate is chemically treated, so that the interfacial bonds can be created. However, it is difficult to use these adhesive systems in minimally-invasive biomedical situations, in which hydrogel must be injected and formed in situ and tissue treatment would impose serious limitations. In Attaching hydrogels to soft internal tissues is crucial for the development of various biomedical devices. Tough sticky hydrogel patches present high adhesion, yet with lack of injectability and the need for treatment of contacting surface. On the contrary, injectable and photo-curable hydrogels are highly attractive owing to their ease of use, flexibility of filling any shape, and their minimally invasive character, compared to their conventional preformed counterparts. Despite recent advances in material developments, a hydrogel that exhibits both proper injectability and sufficient intrinsic adhesion is yet to be demonstrated. Herein, a paradigm shift is proposed toward the design of intrinsically adhesive networks for injectable and photo-curable hydrogels. The bioinspired design strategy not only provides strong adhesive contact, but also results in a wide window of physicochemical properties. The adhesive networks are based on a family of polymeric backbones where chains are modified to be intrinsically adhesive to host tissue and simultaneously form a hydrogel network via a hybrid cross-linking mechanism. With this strategy, adhesion is achieved through a controlled synergy between the interfacial chemistry and bulk mechanical properties. The functionalities of the bioadhesives are demonstrated for various applications, such as tissue adhesives, surgical sealants, or injectable scaffolds.

Temperature evolution following joint loading promotes chondrogenesis by synergistic cues via calcium signaling

“…The ideal construct would be a mechanically capable scaffold that provides an environment for moderate cells adhesion and fairly maintains round morphology of cells. This might be realized by cells encapsulation into an adhesive soft hydrogel ( Karami et al, 2021 ) with endogenous binding sites for cells which is firmly integrated in a stiff and porous 3D support with load-bearing capacity ( Liao et al, 2013 ; Boere et al, 2014 ). The limitation of our porous dissipative hydrogel for this method of construct preparation is its intentional low permeability (order of E –14 m 2 ) to induce frictional drag dissipation.…”

A catechol-chitosan-based adhesive and injectable hydrogel resistant to oxidation and compatible with cell therapy

“…At high shear rates (ν ≥ 10 s -1 ), the viscosity of the pre-gel solutions was significantly lower than that of other recently designed injectable systems (µ ≥ 1 Pa.s compared to µ ≤ 0.02 Pa.s for dhba-CH hydrogels). 64,65 Even at the optimised NaHCO 3 concentration of 50 mM, dhb20-CH yielded weak hydrogels (data not shown). Because DHBA and DHB have the same size and thus create the same steric hindrance at a given χ, we linked the low mechanical properties found for dhb20-CH gels to their high catechol and quinone…”

Functional Macromolecular Adhesives for Bone Fracture Healing

“…28−30 In a broad sense, adhesives for medical applications can be categorized as hemostatic agents, sealants, and adhesives. 29,31,32 So far, only a few commercially available tissue adhesives with registered trademarks and manufacturers are recognized. The most commonly used one is fibrin glue (trade names: Tisseel, Evicel, Cryoseal, etc.).…”

“…When it comes to bone adhesive, the concept of tissue adhesive cannot be circumvented. Tissue adhesives are made of materials that can close soft tissues, such as muscle and skin, and keep wounded tissues from separating through their adhesive force. − In a broad sense, adhesives for medical applications can be categorized as hemostatic agents, sealants, and adhesives. ,, So far, only a few commercially available tissue adhesives with registered trademarks and manufacturers are recognized. The most commonly used one is fibrin glue (trade names: Tisseel, Evicel, Cryoseal, etc. )…”